1. Field of the Invention
The present invention relates to a dust collecting apparatus for use in an air conditioner that includes an ionizer to electrically charge dust particles in air and a metal filter having fine metal fibers disposed at a predetermined interval from a back of the ionizer, in which the metal filter has a polarity opposite to that of the charged dust particles to electrically collect the dust particles.
2. Description of the Related Art
As is well known to those skilled in the art, an inorganic or synthetic fiber filter or an electric collection filter having an ionizer and a collector has been used to collect dust in an air conditioner, in which the inorganic or synthetic fiber filter is formed of natural fibers, glass fibers, or various synthetic resin fibers.
However, the inorganic or synthetic fiber filter formed of natural fibers, glass fibers, or various synthetic resin fibers may be damaged under severe conditions including high temperatures, high pressures, and high wind velocities, and involves some risk. Further, this type of filter is disadvantageous in that it is discarded following use for a predetermined period of time. Accordingly, additional cost is required to manage and ultimately dispose of the above filter. In addition, the environment is contaminated due to the discarded filter.
FIG. 1 illustrates a conventional dust collecting apparatus of an air conditioner. As shown in FIG. 1, the dust collecting apparatus includes an ionizer having discharge electrodes 1 and ground electrodes 2. In the ionizer, when high voltage is applied to the discharge electrodes 1, corona discharge occurs between the discharge electrodes 1 and the ground electrodes 2, resulting in dust particles in air drawn into the air conditioner being electrically ionized. When the ionized dust particles pass through a collector having grounded collecting plates 3 and accelerating electrode plates 4, to which a high voltage is applied, the dust particles are collected onto the grounded collecting plates 3 by the strength of the electric field generated between two polar plates (i.e., the grounded collecting plate 3 and the accelerating electrode plate 4).
The collection efficiency of the collector increases as the area of the collecting plate 3 increases, the flow rate of the dust particles increases, or the space between the two polar plates in the collector decreases. The collection efficiency decreases as an amount of flowing air increases or a flow rate of air passing through the filter increases.
FIG. 2 illustrates another conventional dust collecting apparatus (i.e., a dust collection filter) in an air conditioner, which is used to enhance dust collection efficiency by increasing the surface area of a collecting plate. As shown in FIG. 2, a collecting plate 3 made of aluminum foil is formed into a wave-shaped band, and is attached to an accelerating electrode plate 4, after which the collecting plate 3 and the accelerating electrode plate 4 are wound to form a coil-shaped collector.
The collection efficiency of the conventional dust collecting filter of FIG. 2 drastically decreases as the widths of the collecting plate 3 and the accelerating electrode plate 4 decrease as dust passes through the collecting filter at a constant flow rate. Hence, the width of each collecting plate 3 should be increased, which increase the total volume of the air conditioner. Thus, it is difficult to fabricate a compact air conditioner. In addition, because each collecting plate 3 has a wave shape to maintain a constant space between the collecting plate 3 and the accelerating electrode plate 4, dust does not attach to the collecting plate 3, but, rather, passes between the waves at fast flow rates, thus drastically decreasing the collection efficiency.
Further, the collector of FIG. 2 has a complicated structure because the metal collecting plate made of aluminum foil and the accelerating electrode plate, to which high voltage is applied, are provided separately in the collector. With the aim of increasing the surface area of the collecting plate, a plurality of collecting plates 3 should be provided, whereby a space between each collecting plate 3 and accelerating electrode plate 4 decreases. However, in such a case, arc-discharge is generated between each collecting plate 3 and accelerating electrode plate 4 by application of the high voltage, which inversely charges and again scatters the collected dust particles.
In the case of the coil-shaped collector of FIG. 2 having the collecting plate 3 and the accelerating electrode plate 4 wound together to increase the surface area of the collecting plate 3, the collector has a large volume and weight in the air conditioner. Also, because the collecting plate 3 is not easily separated from the accelerating electrode plate 4, it is difficult to wash the collecting plate 3 separately. Therefore, limitations are imposed on recycling the collecting plate 3 by a back washing process.
On the other hand, the metal plate made of aluminum foil in the collector of FIG. 2 exhibits a dust collecting function only through ionization. Dust particles that are not ionized in the ionizer (not shown) are not filtered by the collector, and thus the collection efficiency becomes low.
Moreover, the conventional dust collecting apparatus of FIG. 1 or FIG. 2 has a drawback of low collection efficiency when the ionizer is not operating properly. That is, when the ionizer is not operating properly, dust particles are not electrically charged and pass through the collector without being collected.
Contained in air drawn into a suction port (not shown) are dust particles as well as offensive odors or VOCs (Volatile Organic Compounds: aromatic compounds, alcohols, hydrocarbons, organic acids, ketones, aldehydes) that are not entirely removed by the above dust collecting filter. Therefore, the conventional dust collecting apparatus has an additional disadvantage in that an additional filtering apparatus is required.